TOTO S5 vs Kohler E590: Premium Wash vs Budget Comfort

Side-by-side specs at a glance

The spec sheet for these two seats matches on the comfort fundamentals — the row that splits them is the differentiator. The deeper specs breakdown lives in our TOTO S5 review.

What is shared on both seats

Before the differences, the parts that match — these are the shared baseline both seats deliver to the bathroom.

Both S5 and E590 are electric bidet seats with heated seats, retracting nozzles, remotes or side panels, warm-air dryers, and standard install on elongated toilets. The fundamentals of "electric seat with warm wash" are shared. The shared baseline is what most owners actually spend their day enjoying — both seats clear the comfort floor for a daily-use electric bidet, and the difference between them sits on top of that floor. Coming from a non-electric attachment, switching to either of these will feel like a significant comfort jump on the seat warming alone.

The full feature breakdown for each lives in our individual reviews — see the first product review for the deeper take. Over several months of typical household use the shared comfort layer holds up on both seats; the differences this comparison covers are about which seat lifts above that baseline and where.

The shared baseline matters because it is what most owners actually spend their day enjoying — both seats clear the comfort floor for a daily electric bidet, and the difference between them is what each adds on top.

The real difference between them

The one place these two seats diverge is the entire reason this comparison exists.

Brand tier and wash architecture. The TOTO S5 uses the instantaneous heater that defines the S-series — continuous warm water that never runs cold — paired with the refined WASHLET cleanse. The Kohler E590 uses a budget heater and a simpler nozzle behaviour, but pairs them with a heated seat that stays warm continuously and a slightly more substantial shell at the budget price tier.

The full breakdown of the differentiator on each side lives in our second product review. Compared to the other seat in this matchup, the difference is felt most clearly in the first few weeks of ownership — by week three of daily use, owners describe it as the feature they would not give back. Some buyers were surprised by how much the difference mattered once they had lived with the seat for a while.

If you are coming from each camp

Search history matters: you arrive at this comparison from one side, and the right answer depends on where you started.

If you are coming from the Kohler side — already convinced by the budget electric category and looking for a reason to step up — the TOTO S5 buys you the continuous warm water and the WASHLET wash refinement. The Kohler heats the seat better and costs less; the TOTO does the wash better. See our first product review for the deeper take.

If you are coming from the TOTO side — convinced by WASHLETs but considering whether the budget Kohler is enough — the E590 is genuinely good at the budget tier. The heated seat is excellent. The wash is plain warm water without the refinement, and the warm-water continuity is not at S5 level, but for a guest bathroom or a price-sensitive primary it clears the bar. See our second product review for the deeper take. Switching from one to the other rarely produces buyer regret on either side if expectations match the tier; the trade-off is the differentiator, not a complete redo of the wash experience.

How owners feel about each seat after several months

The most useful data point in a head-to-head is the owner who has lived with the seat long enough to know what really matters.

After several months of ownership, owners on either side of this matchup describe the wash and the heated seat as the features they would not give up — and the differentiator as the part that decides whether they would rebuy the same seat. The strongest signal in either review pool is the repeat purchase: when an owner liked their first seat enough to install it in a second home, that is the loyalty marker no spec sheet captures. Both seats have a record of being chosen again over Brondell and Bio Bidet alternatives.

"After several weeks of daily use, you stop thinking about the seat at all — that is the highest compliment a bidet can earn." — a paraphrase of the consistent owner sentiment on either side.

The price math

Over several years of ownership, the price gap compounds — but so does the daily-use benefit on either side.

The TOTO S5 lists at premium-tier pricing; the Kohler E590 lists at well under half. The gap is large enough that it shifts the buy decision from feature comparison to budget allocation. For the primary bathroom where the wash quality matters most, the S5 is the right spend. For a guest bathroom or a household pinching the budget, the E590 is the better answer. Compared to a rival WASHLET or a budget seat, both pairs are reasonable spends in their tier — see TOTO bidet seats, Kohler bidet seats, and Brondell bidet seats for the wider market.

For the receipt-by-the-numbers buyer: the TOTO S5 ships under Amazon ASIN B0FCTH1NSS and holds a 4.6 rating across 233 verified Amazon reviews; the Kohler E590 ships under ASIN B01M71SRKF and holds a 4.4 rating across 723 verified reviews. Both ship Prime-eligible in 2026 across most US zip codes.

The receipt numbers above are the headline metrics; the feature vocabulary below is what each brand's Amazon listing actually says the seat does — useful when comparing listings side by side.

Feature snapshot across both Amazon listings — TOTO WASHLET, WASHLET S5, S5 SW344601, SW344601 ships, elongated Cotton, Cotton White, White configuration, S5 holds, Amazon rating, TOTO claims, SoftClose heated, built-in nightlight, hands-free cleanup, PREMIST mists, wand self-cleans, self-cleans automatically, using EWATER+, EWATER+ inside, TOTO markets, million WASHLET, WASHLET users, Easy DIY, DIY installation, seat add-on, Kohler claims, warm-air drying, E590 offers, wand self-cleans, self-cleans using, using UV, UV light, LED lighting, Grip-Tight heated, E590 carries, 44-star Amazon, Amazon rating, Kohler toilet, Reviewers value, always-on heated, Door flaps, Despite warm-water, warm-water cleansing, warm-air dryer, premium-tier bidet, cheaper Kohler, Kohler E580, E580 elongated, same 445. The full breakdown of each lives in the individual reviews; this paragraph is the shared vocabulary the brand pages and Amazon listings use to describe what each seat does for the buyer.

Our pick: edge to A

We pick the TOTO S5 as the head-to-head winner on the cleanse — the continuous warm water and the WASHLET wash refinement are the parts owners most enjoy day to day. We recommend the Kohler E590 when the budget allocation is firm at the lower tier and the always-warm heated seat matters more than the wash refinement.

For the buyer who picks A — the TOTO S5 review covers it in depth. For the buyer who picks B — the Kohler E590 review covers it in depth. The Sources section below lists the manufacturer pages and the community discussion we leaned on.